The Grassland Vivarium is the last to be unlocked in Hogwarts Legacy, but it is more than worth the wait. To get their hands on the Grassland Vivarium, players will have to complete the Phoenix Rising quest which is initiated by talking to Deek after finishing Niamh Fitzgerald's Trial.
The final upgrade is the Mountain Vivarium, and it only becomes available after the Niamh Fitzgerald's Trial quest is finished. Deek will once again have a task for the player called Phoenix Rising, and completing this side quest will ultimately unlock the Mountain Vivarium upgrade later in the winter.
The fourth and last Hogwarts Legacy Vivarium biome that you can unlock takes you to a quaint area nestled on a mountain. To get it, finish the Niamh Fitzgerald's Trial quest, which gives you access to the Phoenix Rising sidequest.
While you can't actually expand your current Vivarium or modify it in any way, you can unlock new ones instead. In total, you can unlock four Vivariums throughout the game to tame all kinds of beasts. One Vivarium can hold as many as 12 animals, but only 4 species.
To unlock the third Vivarium (swamp biome), you need to finish the side quest named Foal of the Dead - that becomes available after the main story chapter dubbed Charles Rookwood's Trial.
Everything You NEED To Know About Your Vivarium in Hogwarts Legacy
Can you have more than 4 species in Vivarium hogwarts?
The initial Vivarium can only contain four distinct species at a time, but there are 13 Beasts you can find and rescue in the game—including the Hippogriffs, Thestrals, and the Phoenix.
The character has an interesting story path in Hogwarts Legacy revolving around his family and past, so you would be missing out on a compelling narrative if you turn him in. If you do turn Sebastian in, it will lock out additional content that could extend your time in the Wizarding World's darker side.
Out of the 13 Beasts present in Hogwarts Legacy, 12 Beasts can be bred. The Phoenix is the only species in the game that can't be bred because it's a one-of-a-kind creature.
There are two types of unicorns — one with a dark coat and one with a light coat — and you can keep them in your vivarium to get Unicorn Hair, which is useful for upgrading high-level gear.
Highwing is a white female Hippogriff in Hogwarts Legacy. She was named by Poppy Sweeting, with whom she has a close relationship. After the main quest The High Keep, she becomes available to the player as a Flying Mount and can be cared for in a Vivarium.
To get the Phoenix in Hogwarts Legacy, you need to complete all of Deek's side missions up to and including the one called Phoenix Rising. You can only start Deek's mission chain after you unlock the Room of Requirement, which happens a few hours into the main story.
The Swamp Vivarium will become available to you during the Foal of the Dead Side Quest, when Deek is teaching you the basics of breeding beasts. Here, you can set up the Breeding Pen with the Breeding Spellcraft you buy from Tomes and Scrolls, if you want.
There are more graphorns, but only one phoenix. There is only one phoenix in the game. Graphorns are technically unlimited and they can be bred - after getting your first one, you'll find a lair in the same area where one graphorn spawns at a time.
How do you get more beast slots in Vivarium Hogwarts Legacy?
If you're getting rid of your beasts because you're running out of species slots, don't worry; completing Deek's side questline will expand your Room of Requirement and add new Vivariums—thus increasing the number of species you can have at once.
This section of IGN's Hogwarts Legacy Wiki Guide breaks down the first vivarium you create in the Room of Requirement: the Forest Vivarium. In order to access this, you'll need to complete The Elf, The Nab-Sack, and the Loom Main Story quest, which follows The Caretaker's Lunar Lament and The Helm of Urtkot.
Like any creature in Hogwarts Legacy, players can breed Unicorns, albeit a bit more time-consuming than the other Beasts, as the process requires an extra step. Unlike other creatures which can be found in groups, only one Unicorn can be seen when visiting its Habitat near Upper Hogsfield.
Finding a shiny Unicorn in Hogwarts Legacy is tough, as there is only one den in the game and the fact that only one Unicorn spawns at a time in the den. While a normal Unicorn is white in color, the shiny Unicorn is brown, almost gold-like in color.
There is a female graphorn that can spawn at the graphorn lair at the south-east corner of the map. Only one graphorn spawns there every time the area resets, and its gender might be random. For me, it was female on the first try.
In case you didn't know, the Basilisk is a giant and powerful snake that lives in the Chamber of Secrets. However, the Basilisk is a rare and deadly creature, and attempting to breed the serpent falls under the Ban on Experimental Breeding. It's fair to say that this is a forbidden creature, and for a very good reason.
The Phoenix is a legendary beast in Hogwarts Legacy and can't be found like other beasts. Not only do you have to complete a special quest to find it, but the Phoenix also cannot be bred.
